Carrie Schwab-Pomerantz, the daughter of financial services icon Charles Schwab, has an MBA, is a certified financial planner and is a senior vice president of the company that bears her father's name. But sometimes even she seeks advice when it comes to investing for retirement.

"I have always been a saver, but it wasn't until my 40s that I got really intentional about my retirement," she says. "I sat down and made sure I was on track and worked with a professional. I was a do-it-yourselfer until my 40s."

Say what? She got investment advice? "You'll find a lot of financial professionals use other professionals to get help. It takes the emotions out of it, and you get better results. Otherwise, it's like a doctor doing surgery on him- or herself."

Schwab-Pomerantz, 54, shares many of her insights on saving for retirement and other financial issues in her new book, The Charles Schwab Guide to Finances After Fifty: Answers to Your Most Important Money Questions, written with Joanne Cuthbertson.

She learned some key values from her father. "My dad was a struggling businessman until I was in my 20s," Schwab-Pomerantz says. "He always taught me to save. He taught me a strong work ethic."

As a child, she babysat, had a paper route and worked in her dad's office when she was 16. "When I was in my 20s and worked for the company, he taught me the importance of diversification. I'm a big believer in creating a diverse portfolio. Having a diversified portfolio of stocks, bonds and cash is one of the most important principles of successful investing. It's how we manage risks."

In turn, she has taught her three children, ages 25, 22 and 17, with husband writer Gary Pomerantz, to work hard and save.

Saving enough, especially for retirement, is a big problem for many Americans, says Schwab-Pomerantz, who is also president of the Charles Schwab Foundation, which oversees financial education programs for teens and adults.

Ideally, "We want to get people to start saving for their retirement when they are younger. If you start in your 20s, and you save 10% to 15% of your income for the rest of your life, you'll have a comfortable retirement," she says. "But if you wait until your 40s to start saving for retirement, you have to increase that to 25% to 40% of your gross income."

The estimates of the amount that people have saved for retirement vary among studies, she says, but according to a Employee Benefit Research Institute survey, about 60% of U.S. workers say they have less than $25,000 in savings and investments (not counting their primary residence and defined benefits such as traditional pensions).

For most people, that won't not be nearly enough. People need to crunch the numbers on how much they'll need and then make a plan on how to reach that amount, she says. "We have found that many people who are in retirement wish they had done a better job planning."

So how much do you need?

"We have a rule of thumb that says in order to feel confident that your money will last throughout retirement, you should save roughly 25 times the amount of your first year's planned withdrawal."

So if you think you'll need $40,000 a year to live in retirement — that's not counting the money you get from Social Security — you will need to save a million dollars, she says. Of course, depending on your situation, you may need more or less.

Another way of thinking about the 25-times guideline is to plan to take out roughly 4% of your assets in your first year of retirement. This 4% guideline is based on probability analysis and builds in the ability to increase your withdrawal every year for inflation, she says. It also assumes you'll have anywhere from 20% to 60% of your money invested in a diversified mix of stocks to make sure it grows enough, Schwab-Pomerantz says.

People who are way behind in saving shouldn't give up. It's never too late to start, she says. A 50-year-old who maxes out his 401(k) contribution could save $17,500 a year plus make an additional catch-up contribution of $5,500 for a total savings of $23,000 a year. Assuming a 6% annual return, by the time that person retires at age 65, he would have saved about $570,000, she says.

She cautions people not to make paying for their kids' college educations a higher priority than retirement savings. "There are so many more options for your child to pay for college — scholarships, grants, loans, working part time — but with retirement you only have one shot and that's your own savings.